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An efficient method has been developed to synthesize well-aligned multi-walled carbon nanotubes (MWCNTs) on a conductive Ta substrate by chemical vapour deposition (CVD). Free-standing MWCNTs arrays were functionalized through electrochemical oxidation with the formation of hydroxyl and carboxyl functional groups. Using a new oven drying technique, we demonstrate that the unidirectionally aligned and laterally spaced geometry of the CNT arrays can be retained after being subjected to each step of electrochemical modification. Samples were analyzed by using a field emission scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transformed infrared (FTIR) and Raman spectroscopy. Useful electrochemical methods for the synthesis of various gold nanostructures onto the aligned MWCNTs were then presented for the first time. The results demonstrated that flowerlike nanoparticle arrays, nanosheets and nanoflowers were obtained on the aligned CNTs under different experimental conditions. These kinds of aligned-CNT/Au nanostructures hybrid materials introduced by these efficient and simple electrochemical methods could lead to development of a new generation device for ultrasensitive catalytic and biological application.

Understanding and improving 3D printing process models are very important for designing building defect‐free 3D printers. Most studies have failed to present detailed process design and modeling of material extrusion (MatEx)‐based additive manufacturing (AM) in a systematic approach that considers all process parameters such as nozzle diameter, nozzle angle, and velocity. It is studied that the accuracy and consistency of a MatEx 3D fabricated product depend on the pressure drop across various nozzle zones. This paper identifies the constraints affecting the performance of the MatEx AM process and presents mathematical modeling related to various process parameters. Also, the paper shows expressions for pinch wheel feed mechanism, liquefier, and nozzle geometry of the MatEx process in terms of independent variables, such as liquefier temperature, nozzle geometry, and feed rate. This will be helpful in computing the precise design parameters of MatEx‐based 3D printers. The complex mathematical expressions developed are pivotal for the effective regulation of the 3D printing process. It not only provides new and better designs for MatEx machines with precise operation and better resolution but also opens the scope for further scientific development to expand the capability of proposed approach for both specific applications and the field.

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